This invention relates to an assembly for transferring solid particulate matter, with the assistance of pressurized airflow into a loading container, which may be a storage container, a processing tank, or other similar vessel. Even more particularly, the present invention relates to an assembly for transferring solid pelletized material, such as for instance a catalyst substance, into a loading container, wherein the pelletized material generates dust during the transfer process.
Many industries require transport, or delivery of solid particles from storage area or delivery container into another storage container or a processing tank. One of such industries is a chemical industry where pre-determined quantities of solid pellets are loaded into a processing vessel or converter. For instance, sulfuric acid manufacturing plants use a vanadium catalyst, which is supplied in a pelletized form in bags or drums. The catalyst pebbles then need to be loaded into the converter or container where a chemical reaction for generation of gases takes place.
Conventionally, acid processing tanks are upright vessels with a closed top. A plurality of levels or beds of catalyst is contained in each converter vessel. The loading takes place through the top of the converter in the first bed of catalyst and through opening in the side wall of the converter in lower beds. During the loading operation, the catalyst pellets, being delivered by gravity, generate a significant amount of dust. The personnel who perform the loading operation, by necessity have to wear face masks, respirators, and similar protective gear to avoid breathing in the dust that heavily permeates the area where the loading takes place.
Similar conditions exist in loading operations of other solid particles, for instance, during grain loading into silos and other storage facilities. The loading space has to be equipped with adequate ventilation to minimize the dust particles retention in the loading area and creation of health hazards in such areas.
A useful assembly for handling solid particulate matter is disclosed in U.S. Pat. No. 6,736,171, which discloses the use of a discharge nozzle carried by a distant end of a discharge conduit. The nozzle is also connected to a dust collection container. A vacuum-assisted suction force is created in the dust collection container to facilitate entrapment of dust particles generated during transfer of the solid material through the discharge container and carrying of the dust particles away from the discharge opening of the discharge nozzle into the dust collection container.
The discharge nozzle of the '171 patent has a double-walled construction with an inner conduit and an outer sleeve with a plurality of air intake openings formed in the body of the sleeve. In this design, the suction force is oriented substantially transversely to the flow of material through the nozzle, and there is no means to regulate the air flow. While the assembly of the '171 patent works satisfactory in many situations, it was noted that the suction force sometimes interferes with the speed of the particle delivery.
The present invention contemplates elimination of drawbacks associated with the prior design and provision of an improved loading assembly that prevents dust from escaping the loading conduits or hoppers and creating hazardous conditions in the loading area.